TestBigMatrix fails on mips64el and ppc64el architectures about simbody

[sherm1]

Is this something that was working previously and stopped working? If so, any idea what broke it? (Simbody code change, build compiler change, etc?)

[merkys]

Yes, TestBigMatrix used to pass on mips64el and ppc64el architectures. Doing some log bisecting I find the following:

Simbody version	C/CXX compiler version	TestBigMatrix
3.6.1	8.3.0	Passed
3.6.1	12.2.0	Failed

Thus it seems that the problem for these architectures is the update of C/CXX compiler from 8.3.0 to 12.2.0.

[sherm1]

I'm not sure what to do with this. The problem appears to be an optimizer bug in the mips and ppc backends for the newer compiler, but I don't have access to those so can't confirm that compiling with optimization off allows the test to pass. Do you have an idea for how to address this problem?

[merkys]

I can try disabling optimization for these architectures just to see if that helps. How can I do that?

[sherm1]

@merkys -- sorry for the delayed response!

As an experiment, please try modifying line CMakeLists.txt:400 at the top level to read
set(GCC_OPT_DISABLE -O1) or -O0 if it still fails at O1.
Then regenerate with CMake and rebuild to see of all tests pass.

If that works we can PR a conditional on the architecture.

[merkys]

Just checked, neither -O1, nor -O0 makes TestBigMatrix pass, alas.

[sherm1]

Rats! That's surprising. Thanks for trying. Is the compiler you're using gcc or clang?

[merkys]

@sherm1 sorry for dropping the ball. I believe gcc is the compiler.